Oxygen Vacancy Formation, Mobility, and Hydrogen Pick-up during Oxidation of Zirconium by Water

Abstract

A comprehensive first principles understanding of the oxidation of zirconium alloys by water was reiterated. Two channels were taken to jointly constitute to the oxidation process: one according to classical oxidation theory involving hydrogen evolution and the second reflected by inwards transport of protons causing hydrogen pick-up. The two were associated with charged and uncharged oxygen vacancies, respectively. The purpose of the present study was to clarify the nature of the effective anode during oxidation of zirconium as to the detailed role of the metal. Oxygen dissolution in the alloy resulted in a “pre-anodic” property associated with the formation of oxygen vacancy VO in the oxide, i.e., preceding VO2+/2e− separation. Atomistic perspective on the metal/oxide interface before nucleation of VO was provided. The rapid convergence of the model interface to bulk properties in spite of the local structural variability provided new insight as to the nature of an amorphous metal/oxide interface.